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CN-122011947-A - Composition for polishing copper interconnection ruthenium-based barrier layer

CN122011947ACN 122011947 ACN122011947 ACN 122011947ACN-122011947-A

Abstract

The invention provides a composition for polishing a copper interconnection ruthenium-based barrier layer, which comprises, by weight, 0.1-5% of silicon dioxide abrasive, 0.01-2% of hydrogen peroxide, 0.01-3% of alcohol amine compound, 0.1-0.3% of potassium ferrocyanide, 0.01-0.3% of 5-methylthio-1H-tetrazole, ammonia water and the balance deionized water, wherein the total mass of the composition is 100%. According to the invention, 5-methylthio-1H-tetrazole is introduced into a polishing system as a copper inhibitor, and potassium ferrocyanide and ethylenediamine are introduced as ruthenium removal promoting components, so that the removal rate of ruthenium can be improved while copper over-removal and galvanic corrosion are inhibited, copper protection and ruthenium removal are simultaneously considered, the planarization treatment of a wafer is realized, and the morphology of dishing pits and etching pits is improved.

Inventors

  • YU ZHENMEI
  • LIU LEI
  • ZHANG ZIXIN
  • MA XINYU

Assignees

  • 兴华清科(天津)电子材料有限公司

Dates

Publication Date
20260512
Application Date
20260331

Claims (10)

  1. 1. A composition for chemical mechanical polishing of a ruthenium-based barrier for copper interconnects, comprising, based on 100wt% of the total mass of the composition: 0.1 to 5wt% silica abrasive; 0.01-2wt% hydrogen peroxide; 0.01-3wt% of alcohol amine compound; 0.1-0.3wt% potassium ferrocyanide; 0.01-0.3wt% of 5-methylthio-1H-tetrazole; ammonia water and the balance of deionized water; the pH of the composition was 9.0.
  2. 2. The composition for chemical mechanical polishing a ruthenium-based barrier to copper interconnect of claim 1 wherein the silica abrasive has a particle size of 30 nm to 100nm.
  3. 3. The composition for chemical mechanical polishing a ruthenium-based barrier layer for copper interconnect of claim 1, wherein the alcohol amine compound is one or more selected from the group consisting of monoethanolamine, diethanolamine, tetrahydroxyethylethylenediamine, ethylenediamine, triethanolamine, diglycolamine, monoisopropanolamine, N-methyldiethanolamine, dimethylethanolamine and diethylethanolamine.
  4. 4. The composition for chemical mechanical polishing a ruthenium-based barrier to copper interconnect of claim 3 wherein the alcohol amine compound is ethylenediamine.
  5. 5. The composition for chemical mechanical polishing a ruthenium-based barrier to copper interconnect of claim 1 wherein the silica abrasive is present in an amount of 5 wt.% and the hydrogen peroxide is present in an amount of 0.15 wt.%.
  6. 6. The composition for chemical mechanical polishing a ruthenium-based barrier to copper interconnect of claim 4 wherein the ethylenediamine is present in an amount of 0.12 wt.%.
  7. 7. The composition for chemical mechanical polishing a ruthenium-based barrier to copper interconnect of claim 1 wherein the potassium ferrocyanide is 0.20 wt.% and the 5-methylsulfanyl-1H-tetrazole is 0.20 wt.%.
  8. 8. A chemical mechanical polishing method of a copper interconnection ruthenium-based barrier layer, which is characterized in that the composition for chemical mechanical polishing of the copper interconnection ruthenium-based barrier layer is adopted to chemically mechanical polish a wafer to be polished, wherein the wafer to be polished comprises a copper-coated silicon substrate wafer and a ruthenium-coated silicon substrate wafer.
  9. 9. The chemical mechanical polishing method as set forth in claim 8, wherein the chemical mechanical polishing process has a working pressure of 1-2psi, a wafer rotation speed of 70-90rpm, a polishing disk rotation speed of 80-100rpm, a composition flow rate of 200-400 mL/min, and a polishing time of 60s.
  10. 10. The chemical mechanical polishing process of claim 8, wherein the Ru/Cu removal rate selectivity is controlled by adjusting the content ratio of 5-methylthio-1H-tetrazole to potassium ferrocyanide in the composition to improve dishing and etch pit morphology on the surface of the wafer to be polished.

Description

Composition for polishing copper interconnection ruthenium-based barrier layer Technical Field The invention relates to the technical field of semiconductor polishing, in particular to a composition for polishing a copper interconnection ruthenium-based barrier layer. Background Chemical Mechanical Planarization (CMP) is a critical process step in integrated circuit fabrication, and has an important impact on wafer surface planarization, subsequent process accuracy, and device yield. In advanced copper interconnect technology, ruthenium is widely used as a barrier layer material in copper interconnect structures due to its low resistivity, high thermal stability, good adhesion to copper, and direct electroplating. In the CMP process of copper interconnect ruthenium-based barrier layers, ruthenium is an inert metal and the removal rate is typically lower, while copper is a more reactive metal and is more easily removed during polishing. Meanwhile, potential difference exists between ruthenium and copper, galvanic corrosion is easy to occur during polishing, so that dishing pit and etching pit morphology are further increased, and an ideal planarization effect is difficult to obtain. In general, related polishing solution systems are focused on improving the removal rate of ruthenium or on inhibiting copper corrosion, but it is difficult to simultaneously realize effective removal of ruthenium, inhibition of copper and adjustment of the selection ratio of Ru/Cu removal rate, so that targeted planarization treatment is difficult to realize according to different initial wafer morphologies. On the other hand, part of polishing solution system additives are more in variety, complex in system and insufficient in stability, and are not beneficial to practical process application; to this end, a composition for polishing a copper interconnect ruthenium-based barrier layer is presented. Disclosure of Invention In view of the foregoing, the present invention provides a composition for polishing a ruthenium-based barrier layer for copper interconnects that provides at least one advantageous option for the technical problems of the prior art. The first aspect of the invention provides a composition for polishing a copper interconnection ruthenium-based barrier layer, which comprises, based on 100wt% of the total mass of the composition, 0.1-5wt% of a silicon dioxide abrasive, 0.01-2wt% of hydrogen peroxide, 0.01-3wt% of an alcohol amine compound, 0.1-0.3wt% of potassium ferrocyanide, 0.01-0.3wt% of 5-methylthio-1H-tetrazole, ammonia water and the balance deionized water, wherein the pH value of the composition is 9.0. The silicon dioxide abrasive in the composition plays a role in mechanical removal, the surface of a wafer is oxidized by hydrogen peroxide, the removal of ruthenium is promoted by an alcohol amine compound and potassium ferrocyanide, and the copper surface is protected by 5-methylthio-1H-tetrazole, so that the cooperative regulation and control of copper removal inhibition and ruthenium removal promotion are realized in the same polishing system. Further, the particle size of the silica abrasive is 30-100nm. The silicon dioxide abrasive with the particle size range is beneficial to considering the polishing removal capacity and the surface quality, and improves the planarization effect of the barrier layer in the polishing stage. Further, the alcohol amine compound is one or more selected from monoethanolamine, diethanolamine, tetrahydroxyethyl ethylenediamine, triethanolamine, diglycolamine, monoisopropanolamine, N-methyldiethanolamine, dimethylethanolamine and diethylethanolamine, and can be used as a complexing agent for ruthenium metal. Furthermore, the alcohol amine compound is ethylenediamine, and when the ethylenediamine is matched with hydrogen peroxide, potassium ferrocyanide and 5-methylthio-1H-tetrazole, a relatively stable alkaline polishing system can be formed, and the removal rate of the barrier layer polishing stage can be regulated and controlled. Further, the content of the silica abrasive was 5wt%, and the content of the hydrogen peroxide was 0.15wt%. Further, the content of ethylenediamine is 0.12wt%. Further, the content of the potassium ferrocyanide is 0.20wt%, and the content of the 5-methylthio-1H-tetrazole is 0.20wt%; Under the above proportioning condition, the 5-methylthio-1H-tetrazole has better copper inhibition effect, the potassium ferrocyanide has more obvious promotion effect on ruthenium, and is beneficial to obtaining better Ru/Cu removal rate selection ratio and better dishing pit and etching pit repairing effect. In a second aspect, the present invention provides a chemical mechanical polishing method for a ruthenium-based barrier layer of a copper interconnect, wherein the chemical mechanical polishing method is used for performing chemical mechanical polishing on a wafer to be polished by using the composition of any one of the above, and the wafer to be polished co